Interpretive Summary: Hydrodynamic pressure processing (HDP) has been used to tenderize various cuts of fresh and frozen/thawed meat. HDP treatment of pork ham has not been studied. Sixteen hams obtained from a larger study were divided into control and HDP treatment groups. A plastic explosive container fitted with a flat reflector plate was used to HDP treat hams which were then brine injected and smoke-cooked (68.3°C). No significant difference between control and HDP hams was found for brine uptake, smoke-cook loss, processing yield, purge after 18 hrs or 5 days, and water holding capacity. The tenderness and texture of the hams were not affected by HDP treatment. These results indicate that use of HDP before processing hams does not adversely or favorably affect ham processing parameters, color or textural quality.

Technical Abstract:
Hydrodynamic pressure processing (HDP) has been used to tenderize various fresh and frozen/thawed whole muscle cuts of meat. During HDP, there is microscopic tearing of the myofibrillar structure which results in tenderization. It has been proposed that this tearing would result in improvements to processing parameters and texture of processed meat; however, the effect of HDP on further processed meat products is not well known. It was hypothesized that the HDP treatment before processing would improve tenderness and processing characteristics of hams. Sixteen frozen green hams obtained from a larger study evaluating transgene and dietary conjugated linoleic acid supplementation were divided into two balanced groups for control and HDP. For each genetic/diet group, HDP treatment was assigned to two hams and the remaining two hams served as controls. Hams designated for HDP were vacuum packaged, heat shrunk and placed on the bottom of a 98-L plastic explosive container filled with water and 100 g of binary explosive was detonated to create the shock wave. Immediately after HDP treatment, control and treated hams were brine injected to 115 percent of original weight. The hams were intermittently tumbled under vacuum for two hours, placed in ham stockings and then smoke-cooked to 68.3°C. After chilling, hams were cut into 2.5 cm thick slices and evaluated for processing parameters, water holding capacity, color, Warner-Bratzler shear force (WBS) and Texture Profile Analysis (TPA). Testing parameters were not affected, with any practical significance by genetic background or diet. No significant difference between control and HDP hams was found for brine uptake, smoke-cook loss, processing yield, purge after 18 hrs or 5 days, and water holding capacity. Color (L, a*, b* values) was not significantly affected by HDP treatment. There were no significant differences between HDP treated and control hams for WBS and TPA hardness, cohesiveness, chewiness, and gumminess. However, HDP treated hams were less springy (P<0.05) than controls (0.57 vs. 0.61 mm). These results indicate that use of HDP before processing hams does not adversely or favorably affect ham processing parameters, color or textural quality.